1. Tissues!

2. Body Organization Cell – Tissue – Organ – Organ System - Body
Tissues: Many similar cells that perform a specific function
Tissue Types
1. Connective – Blood, Bone, Cartilage, Ligaments, & Tendons
2. Nervous – Tissue that transmits and receives messages or impulses (brain, spinal cord)
3. Epithelial – Skin
4. Muscle

3. Ligaments – join bones to other bones
Skeletal System
The skeletal system consists of 206 bones. At birth humans have 270 bones but many bones fuse together during growth.
Ligaments – join bones to other bones
Cartilage - soft portion on the tips of all bones and in the nose and ears (doesn’t contain calcium)
 Skeletal System Functions
1. support
2. protection
3. produces blood cells

4. Spongy bone – the soft inner portion of the bone
Bones have two parts:
Spongy bone – the soft inner portion of the bone
- yellow marrow that stores fat
- red marrow where red & white blood cells are manufactured
Compact Bone – the hard outer portion of the bone
- contains Haversian canals which contain blood vessels
Why would there need to be blood vessels in bones?
Osteocytes (bone cells) – need oxygen and food for energy

5. Development of Bones
In the second month of development bone starts to form where before the embryo had only a cartilage skeleton
Ossification – is the process of cartilage turning into bone
Epiphyseal plate is a layer of cartilage found at the end of each bone where growth takes place. Cells in this area undergo mitosis
Divisions of these cells cause the cartilage to grow and the bones to lengthen as the bone cells ossify 
Growth stops when these cells stop dividing
Bones continue to grow in width throughout life growth in length stops at 25 if not sooner.

6. Four major types of joints:
The place where bones meet is a joint
Joints can be movable and immovable
Where are immovable joints?
Four major types of joints:
1. Hinge – elbow, knee, and ankle
2. Pivot – neck
3. Ball-and-socket – hip and shoulder
4. Gliding – carpal and tarsal bones
Cartilage and synovial fluid (the WD-40 of your body) keep joints moving smoothly

7. Skeletal System problems Sprain – A stretch or tear of a ligament
Arthritis – when joints become swollen or painful
Rheumatoid arthritis – cartilage becomes swollen. Eventually it is replaced by bone, which fuses and prevents movement

8. Osteoarthritis – when cartilage wears away and bones rub together

9. Osteoporosis – a person loses bone density (usually begins around 40)
More common in women because they lose their ability to absorb Calcium efficiently when they have children
THANK YOU MOM!!

10. The body has more than 600 muscles (35-45% of body weight)
The Muscle System
The body has more than 600 muscles (35-45% of body weight)
Functions of Muscle System
1. Movement – main function
2. Digestion, Breathing, Heart Beating etc
3. Protection of internal organs
4. Sitting & Standing

11. Muscles only pull a bone Muscles CANNOT push a bone
Muscles only pull a bone
Muscles CANNOT push a bone
This is why muscles act in pairs
One muscle to extend
One muscle to bend

12. 3. Cardiac Muscle – heart muscle
Muscle Types
1. Skeletal Muscles – move bones attached directly to bones or by a tendon
2. Smooth Muscle – found in internal organs (digestive tract, arteries, respiratory system)
3. Cardiac Muscle – heart muscle
Smooth and Cardiac are both involuntary
What does involuntary mean?

13. How Muscles Contract:
1. A nerve impulse transmitted to the muscle cell by a nerve.
2. The nerve releases Calcium into the cytoplasm of the muscle cell
3. Calcium attaches to molecules located in the cytoplasm called actin (protein)
4. ATP connects to myosin (protein)
What does ATP do?
5. Using the energy from the ATP the myosin (protein) pulls the actin & the muscle contracts
6. When the message from the brain ends the Calcium leaves and the muscle relaxes

14. Exercise
With aerobic exercise, chest muscles can be strengthened so that more air enters the body. This type of exercise helps your cardiovascular endurance.
Why would this help?
Resistance (anaerobic) exercise like weight lifting increases muscle size and strength but it does not increase the amount of oxygen that enters the body.
 Anabolic steroids increase the size and strength of your muscles, synthetic chemicals (that resemble testosterone) trick your muscles into growing larger. They also cause many irreversible side effects including cancer, heart disease, and altered sexual development.

16. Muscle Problems
Shin Splints – inflammation of the tendons on the inside front of the lower leg, muscle strain , overuse injury 
Muscle Cramps – occurs when a muscle cannot relax
Muscular Dystrophy – muscle tissue degenerates and is replaced by fatty tissue

17. The Skin is the human body's largest organ
Integumentary System
Covers the body
Made up of the skin, hair, nails, & a variety of glands
The Skin is the human body's largest organ
The most important function is protection.

18. Controls the body through hormones
Endocrine System
Controls the body through hormones
Example
The hormone melatonin, which secreted by a gland in the brain called the pineal gland, is secreted at night when light is absent or dim. Melatonin is what makes us feel tired